JPH1119998A - Composite molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a structure which has good heat resistance and high strength and does not generate cracking and others in forming by a method in which a composite sheet comprising a thermoplastic resin and reinforcing fibers is formed in a desired cross-sectional shape, a thermoplastic resin is extruded on the surface of the sheet for coating, and reinforcing short fibers are oriented randomly at least on a forming part. SOLUTION: The surface of a core material 1 which is composed of a thermoplastic resin such as a vinyl chloride resin and an acrylic resin and formed to have a U-shaped cross section is extrusion-coated with the skin layer 2 of a thermoplastic resin having good weatherability such as a vinyl chloride resin and an acrylic resin. The core material 1 is composed of short fibers 1a and long fibers 1b including inorganic fibers such as carbon fibers and metal fibers and Kevlar and cotton fibers and a thermoplastic resin 1c, and the short fibers 1a are oriented randomly and arranged only near the corner parts of the core material 1. The long fibers 1b are oriented in the longitudinal direction of the molding and arranged in the parts where the short fibers are absent. The generation of breaking and cracking in the formed parts is prevented, and the product has good molding stability in forming and excellent quality including strength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite molded article in which a reinforcing core material is coated with a thermoplastic resin and which has excellent low elasticity and flame retardancy.

[0002]

2. Description of the Related Art Thermoplastic resins, for example, vinyl chloride resin, are among the general-purpose plastics because they have excellent water resistance, flame retardancy, good mechanical properties, and are relatively inexpensive. Widely used as a material.
For example, rain gutters are conventionally generally formed by extrusion using hard vinyl chloride.

[0003] Although rain gutters are flame-retardant,
Since the heat resistant temperature is 60 to 70 ° C. and the coefficient of linear expansion is as large as 7.0 × 10 ⁻³ (1 / ° C.), when such a vinyl chloride resin is used as a material for the rain gutter, Because it is attached to the eaves, it is easily deformed by heat such as direct sunlight, and it may not function as a rain gutter due to cracks and warpage due to thermal expansion and contraction. There is a problem that is poor.

[0004] As a general measure to solve such a problem, a composite sheet comprising a thermoplastic resin and long fibers oriented in one direction or a plurality of directions is formed, and the surface thereof is extrusion-coated with the thermoplastic resin. Is performed.

[0005]

By the way, the composite sheet comprising the long fibers and the thermoplastic resin as described above is formed into a long object having a uniform sectional shape such as a rain gutter and having a uniform cross section. As shown in FIG. 5A, when the long fibers of the composite sheet are oriented in parallel to the shaping portion, tears occur between the fibers, and FIG. As schematically shown, when the fiber is oriented in the other direction, there is a problem that the fiber is broken at the shaping portion and the strength of the composite molded product cannot be exhibited.

The present invention has been made in view of such circumstances, and has a structure which is excellent in heat resistance, has no breakage during forming, and has excellent strength, and is particularly suitable for rain gutters and the like. The purpose is to provide suitable composite molded products.

[0007]

Means for Solving the Problems In order to achieve the above object, the composite molded article of the present invention has a composite sheet comprising a thermoplastic resin and reinforcing fibers formed into a required cross-sectional shape, and
The thermoplastic resin is extrusion-coated on the surface thereof, and the composite sheet is characterized in that the reinforcing short fibers are randomly oriented at least in the shaped portion.

In the present invention, in the composite sheet coated with a thermoplastic resin to form a core material, the short fibers to be contained in at least the shaped portion thereof include inorganic fibers such as carbon fibers, metal fibers, and glass fibers; , Cotton fibers and the like.

[0009] The fiber length and diameter of the short fibers are appropriately selected according to the required performance of the core material.
0 μm and a fiber diameter of 5 to 50 μm are often used.

The composite sheet used in the present invention is:
There is no particular limitation on the form or orientation of the reinforcing fibers other than the imprinted portion, and the long fibers may be oriented in a fixed direction, or the short fibers may be randomly oriented throughout.

The thermoplastic resin constituting the composite sheet serving as the core material is appropriately selected depending on the fusing property and the moldability with the thermoplastic resin covering the surface thereof, but is generally selected from a vinyl chloride resin and an acrylic resin. , PET (polyethylene terephthalate), PP (polypropylene), PE (polyethylene), nylon and the like.

When forming the composite sheet serving as a core material, in addition to powder impregnation and liquid impregnation, a thermoplastic resin is formed into short fibers, which are mixed with reinforcing short fibers by air stirring or the like. -A method such as molding into a sheet by pressing can be adopted.

As the thermoplastic resin covering the surface of the composite sheet after shaping, vinyl chloride resin, acrylic resin,
It is desirable to use a resin having good weather resistance such as a copolymer thereof, a nylon resin and the like.

According to the composite molded article of the present invention having the above-described structure, since the short fibers are randomly oriented at least in the portion where the composite sheet is formed, the composite sheet is torn at the time of forming or the fibers are not formed. There is no problem such as being broken at the shaped portion and failing to exhibit strength. Therefore, a composite molded article having excellent molding stability, high strength, low elasticity and excellent heat resistance can be obtained.

[0015]

EXAMPLES Examples of the present invention will be described below together with comparative examples. (Embodiment 1) FIG. 1 shows a partially cutaway sectional view of a composite molded product according to an embodiment of the present invention.

The surface of the core material 1 having a substantially U-shaped cross section is
It is extrusion-coated with a skin layer 2 made of a thermoplastic resin. The core material 1 is composed of short fibers 1a, long fibers 1b, and a thermoplastic resin 1c, and the short fibers 1a are randomly oriented. Corner portions of the core material 1, that is, shaping portions in a core material forming step described later. Was arranged only in the vicinity of. In addition, the long fibers 1b were oriented in the longitudinal direction of the molded product, and were arranged in portions other than the portion where the short fibers 1a were arranged.

The material of the short fiber 1a and the long fiber 1b constituting the core material 1 is carbon fiber, respectively, and the thermoplastic resin 1c is PET (polyethylene terephthalate).
The thermoplastic resin of the skin layer 2 was a vinyl chloride resin.

The above embodiment of the present invention can be manufactured by using, for example, a core material forming apparatus shown in FIG. 2 and a core material forming extrusion coating apparatus shown in FIG. The core material forming device converts randomly oriented reinforced short fibers and reinforced long fibers parallel to each other,
An unwinding machine 11 for unwinding a mat M formed by mixing short fibrous or powdery thermoplastic resin, and heating the mat M unwound from the unwinding machine 11 to produce a mat M
A heating furnace 12 for melting the thermoplastic resin in the inside, a heating press roll 13 for heating and pressurizing the inside of the mat M passing through the heating furnace 12, a cooling press roll 14 disposed adjacent to the heating roll press 13, and A winding machine 15 for winding the composite sheet S obtained through the cooling press rolls 14 is a main component.

Using the above-mentioned core material forming apparatus, the carbon fiber 1a randomly oriented at the position corresponding to the corner portion of the molded product as described above is used as the mat M, and the mat M is placed at the position corresponding to the other portion. The composite sheet S was manufactured by arranging the carbon long fibers 1b oriented in one direction.

The core material extruding and coating apparatus is a feeding machine 21 for feeding the sheet S from a roll around which the composite sheet S obtained by the above-described core material shaping device is wound, and a composite material fed from the feeding machine 21. A shaping device 22 for shaping the sheet S into a required cross-sectional shape, an extrusion coating die 23 for extruding a thermoplastic resin on both the front and back surfaces of the formed sheet S, and cooling of the laminate that has passed through the extrusion coating die 23 Sizing device 24 for sizing the product, and a take-off device 25 for picking up a product W obtained through the cooling sizing device 24
Is the main component.

Here, the core material shaping device 22 is a device for gradually shaping the sheet S into a required cross-sectional shape by, for example, a roll or a block-shaped shoe. The shape may be heated or the whole may be heated.

The extrusion coating mold 23 continuously extrudes the molten thermoplastic resin P on both the front and back surfaces of the composite sheet S as a core material by a crosshead die, and cleans the surface of the sheet S with the thermoplastic resin P. The surface of a core material 1 obtained by shaping the composite sheet S into a substantially U-shaped cross section by a core material forming device 22 is extruded with a vinyl chloride resin as a skin layer 2, and FIG. The indicated composite article was obtained.

(Example 2) As shown in a partially cutaway cross-sectional view in FIG. 4, the reinforcing fibers disposed on the core material 1 are made only of randomly oriented short carbon fibers 1a, and are entirely formed on the core material 1 '. It was the same as Example 1 except that it was arranged.

(Comparative Example 1)
Example 1 was the same as Example 1 except that only the long carbon fiber 1b oriented in the longitudinal direction (parallel to the shaping portion) of the molded product was used.

(Comparative example 2)
Except that only the long carbon fiber 1b oriented in the direction perpendicular to the longitudinal direction of the molded product (the direction perpendicular to the shaping portion) was used.
Same as Example 1.

For each of the above Examples and Comparative Examples, the results of evaluating the stability of the composite sheet S during shaping are shown in Table 1 below.
Shown in

[0027]

[Table 1]

As is clear from Table 1, in each of the examples of the present invention, no tearing or cracking occurred during the shaping of the composite sheet, whereas in each comparative example, the tearing or cracking of the composite sheet occurred. It occurred and the molding stability of the examples of the present invention could be confirmed.

[0029]

As described above, according to the present invention, the randomly oriented short fibers are arranged at least in the shaping portion of the composite sheet made of the reinforcing fiber and the thermoplastic resin.
There is no occurrence of tearing or cracking in the shaped portion, and the molding stability during shaping is excellent, and at the same time, the quality such as strength as a product is also excellent.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing the structure of a first embodiment of the present invention.

FIG. 2 is an explanatory view of a core material forming apparatus used in Example 1.

FIG. 3 is an explanatory view of a core-shaped extrusion coating apparatus used in Example 1.

FIG. 4 is a partially cutaway sectional view showing the structure of a second embodiment of the present invention.

FIG. 5 is a schematic explanatory view in the case of using a long fiber oriented in one direction as a core material, where (A) is oriented parallel to a shaping portion and (B) is a direction orthogonal to the shaping portion. Illustration when oriented to

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core material 1a Short fiber 1b Long fiber 1c Thermoplastic resin 2 Skin layer 11 Payout machine 12 Heating furnace 13 Heating roll press 14 Cooling roll press 15 Winding machine 21 Feeding machine 22 Shaping device 23 Extrusion coating die 24 Cooling sizing device 25 Take-up machine S Composite sheet P Thermoplastic resin

Claims (1)

[Claims] 1. A composite sheet comprising a thermoplastic resin and a reinforcing fiber is formed into a required cross-sectional shape, and the surface thereof is extrusion-coated with a thermoplastic resin. A composite molded article characterized in that reinforced short fibers are randomly oriented in portions.